OMC 3.0 will not fire or run.

[94fwfreedom]

1994 omc parts on an 1989 merc. Starter will turn over engine, can hear firing, engine is shaking, smoke comes from exhaust, but it does not catch and run. Confirmed TDC on #1 cylinder. Did voltage test on purple and pink wire on coil and (HEI) distributor, and both have 12 volts. Getting fuel, and the smoke should mean spark. It is puffing out of the carb as well. Firing order 1342, rotation clockwise on distr. Got new gas, and distr.position has been fine tuned to no immediate results. Please help....thanks.

 

[94fwfreedom]

Re: OMC 3.0 will not fire or run.

Little more info...this is a 1994 four winns with an 3.0 l motor, which I replaced with a running 3.0 mercruiser. The donor motor used the DDIS ignition, and ran fine in the old boat. Omc motor has HEI Ignition and the HO manifold with 2 barrel carb.
I have read Don's posts and have tried to check compresion stroke with finger, but motor will not run. Pulled valve cover to confirm engine is on compression stroke. Appears that I was 180 degrees off on the distributor setting, so I rotated motor one full turn and watched rockers loosen up as they allowed the number one cylinder's valves close. Now reset distr. and motor makes no attempt to fire. I do hear burping out of exhaust, but no smoke indicating ignition.
Before I did this (moving distr. 180 degrees, original post) it tried to run, but shoot gas out of the carb, and the even caught fire in the carb!

 

[Howard Sterndrive]

Re: OMC 3.0 will not fire or run.

Are you using a timing light to set the timing?
Did you check the compression of this 89 engine?
Do you have spark at the plugs?

 

[jerryjerry05]

Re: OMC 3.0 will not fire or run.

Possible the shift interupt switch is engaged, stalling the motor???
You don't check comp when running.
Any motor with bad comp will blow your finger off the hole.
Remove the plugs,then unhook the coil.
Install a screwin guage and test.
Possibly the timing out 180d??

 

[94fwfreedom]

Re: OMC 3.0 will not fire or run.

Thanks for the replies. The motor ran great in the donor boat, so I did not think that I needed to worry about compression. I will did so today.
Now what would cause so much gas to pop out of the top of the carb when trying to crank, and also causing flames in the carb? Would that mean the timing is 180 off, right?

I am just trying to eliminate one step at a time (fuel, fire comp.). I have used. Timing light on spark plug #1 wire, and it lights up with the timing marks while cranking. This would mean I am firing at the plugs, correct?

 

[Howard Sterndrive]

Re: OMC 3.0 will not fire or run.

Now what would cause so much gas to pop out of the top of the carb when trying to crank,

Ignition timing wouldn't *usually* cause gas to blow back out the out the carb, but possible.

Improper camshaft timing or valve timing/adjustment could.

Yes to the spark at the plug - but whether it's hot or dull (a spark tester is a handy tool - or someone with pliers and gloves holding a spark plug against the block), it will trigger the timing light, and you could still be 180 out, but it sounds like you eliminated that issue.

I think I would start fresh at the ignition timing to #1 TDC compression stroke again.

and unplug the ESA module just to be sure it's not causing any weirdness as Jerry eluded to- disconnect the tach too while you're at it. A Faulty tach can goof up the ignition.

how old is your gasoline? I guess we know it burns, eh...

 

[94fwfreedom]

Re: OMC 3.0 will not fire or run.

Guys,

What is the chance of the engine being flooded due to the fact that the intake and carb are off the omc motor which was an H.O.3.0 liter, with small exhaust and intake ports, and the 1989 3.0 liter has the larger port style head? I asked my machinist, and he said I should be ok, but...

Also, the gas is fresh, I pumped the tank dry and filled her up with 93 gas from the pump.

I will try to locate the ESA module and the tac wire to disconnect. I have a pre 1994 wire diagram, and have already ran across the ESA plug.

Thanks for the help!

 

[Howard Sterndrive]

Re: OMC 3.0 will not fire or run.

cold engines love being flooded... that's the whole idea of a choke, but with all the cranking, it is a good practice to pull the plugs and blow them off with compressed air or what have you.

 

[PaJon]

Re: OMC 3.0 will not fire or run.

Double and triple check the firing order and that the spark plug wires are on the correct plugs.

 

[Howard Sterndrive]

Re: OMC 3.0 will not fire or run.

you using the old starter? didn't buy a reverse rotation one by accident?

 

[jerryjerry05]

Re: OMC 3.0 will not fire or run.

They make a reverse rotation3.0?

 

[94fwfreedom]

Re: OMC 3.0 will not fire or run.

No, the starter is the mercruiser one, which started the engine in the other boat with all the merc components. I did notice the new plugs coated over with black stuff. I will clean them and try again. Firing order 1342, rotation on engine is LH, pulley turning clockwise viewed from front of engine. Distr. rotated clockwise as viewed from top. Set up notch on harmonic damper to TDC or 0 on timing mark, should be third pointer on timing tap, and hope for the best. That's what I have been doing, also shifter in neutral with some gas or no gas or pumping. Also turned distributor a few degrees hoping for a fire....
Today I will disconect the ESA and tac. Thanks!

 

[Howard Sterndrive]

Re: OMC 3.0 will not fire or run.

sounds like you're doing everything by the book spot on there, 94wfreedom.

They make a reverse rotation3.0?

no, but they make a reverse rotation starter that will fit a 3.0

 

[94fwfreedom]

Re: OMC 3.0 will not fire or run.

GOT IT STARTED!!!!!!!!

It was none of the above, well sorta....

Somehow the harmonic balancer timing mark was almost 180 out of alignment with true top dead center of #1 piston. I only realized this after I kept repeatedly turning the motor by hand and watching the valve train move and noting where the piston was in relationship with the original noth in the harmonic balancer pulley. I reset the distributor, and with the first hit of the key it fired right up. Now, why is my timing mark notch off?? I am guessing this motor with 700 hours has already been rebuilt by a car mechanic, and he must have gotten the cam and crank alignment off.

Bad news now, I tried to set base timing and think I blew up my ignition module. I put the two white jumpers on the right most two studs, and hooked the G terminal to 12 volt. Bum, and it sparked, and shut right off. Now no spark. Off to the auto parts store for a new module.

Btw, check out what the squirrels left me in my exhaust.....

 

[Howard Sterndrive]

Re: OMC 3.0 will not fire or run.

hey good shootin'. Must be a will-fit balancer or it has slipped on the hub.

if the balancer is okyou can use a timing tool on #1 and mark a new tdc on the hub. then measure and calc the 8 or 10 degrees advance you'll need

 

[94fwfreedom]

Re: OMC 3.0 will not fire or run.

Thanks, yes I did and she runs great now. Also, I did blow up the ignition module during the base timing procedure, so if you have a motor the cranks and cranks but has no spark, that could be the cause. The auto parts store can test the module, if its bad order a boat replacement from here!